Axle Ratio and tow rating

Denny & Jami wrote:

Sport45 wrote:
I'm just trying to call it what it is. The power doesn't change. You just swap rpm for torque.

That's how the 400hp turbo-diesel climbs the hill at 50mph in 4th while the 150hp hot water six in can only make 20 mph in 1st. Gearing down won't give the diesel more power, it would just slow it down.

Simple example you need to torque a bolt to 1000 you use a 10 to 1 multiplier so you only have to exert 100 ft lbs to get that torque. If you go to a 5 to 1 multiplier you would need 200 ft lbs to gain the same same torque.

The lower gears affect every gear all the time. Diesels have to be geared different than a gas motor because of their rpm operating range, gears that work for diesels aren't the best for gas motors just like gears for gas aren't the best for diesels.

Denny

You're absolutely right.

The engineer in me just got hung up on the "power" term.

Power, force, torque, and work are terms with specific (and different) meanings in my line of work.

In your example with the torque multiplier above it takes twice the force with the 5-1 vs the 10-1 multiplier. The power used relates to how fast you turn the wrench. If you turn it at twice the speed using the 10-1 multiplier the power is the same. If you turn the wrench the same speed in both cases the 10-1 multiplier is using half the power. (Because you're turning the bolt half as fast.)